Lucia Felix, a 15-year-old Mozambican girl, dreams of returning to her village school but instead she must prepare for motherhood after she was chosen for an arranged marriage and became pregnant.

She is one of the millions of "child brides" across Africa who are married before their 18th birthday, with many already wed when they are younger than 15.

This week, the African Union will meet in Zambia to hold its first conference on "Ending Child Marriage in Africa" -- a small step in efforts to protect girls such as Lucia.

"One day, a young man arrived here to choose a wife from several girls and he chose me. Then I got pregnant," she told AFP, speaking under a mango tree in the courtyard of her family's home in the southern village of Jangamo.

Lucia, who is eight months' pregnant, had just returned from the doctor after contracting malaria and she complained of pains in her belly.

Millions of "child brides" across Africa are married before their 18th birthday.

"I'm afraid because I'm still a child and I fear I won't be able to take care of my baby," she said.

"I want to go back to school and to study to become a teacher."

The African Union says about 14 million under-age girls are married on the continent each year -- almost all of them forced to by their parents, often against laws that are rarely enforced.

'Rights violation'

"Child marriage is a human rights violation that robs girls of their rights to health, to live in security, and to choose if, when and whom to marry," the AU said ahead of the meeting on Thursday and Friday in Lusaka.

"It is a harmful practice which severely affects the rights of a child."

The meeting will gather representatives from member states, first ladies, UN officials and civil society groups to discuss how to change long-established cultural norms and how to eventually end child marriage altogether.

Lucia's mother, Zaida Zunguze, admits she first supported her daughter's marriage to her 20-year-old suitor, but said that she wanted Lucia to wait until she turned 18.

"She's still a child, she knows nothing. I want to continue teaching her how to take care of her house," Zaida said, sitting on a mat next to Lucia.

"I'm worried because the man said he would provide for the baby, and now he doesn't say anything."

Lakshmi Sundaram, executive director of Girls Not Brides.

The legal age of marriage in Mozambique is 18, or 16 with parental consent, but nearly half the girls are married in traditional ceremonies before they turn 18.

According to the last national census conducted in 2011, about 14 percent are married before the age of 15.

"The concept of the child here is different. As soon as they show the first signs of puberty, they are already considered an adult," Pascoa Ferrao, director of the social action department in the southern city of Inhambane, told AFP.

"(Child marriage) has often to do with economic circumstances. If a girl is married off, then there's one less mouth to feed.

"It leads to increased child mortality because teen mums don't know how to take care properly of their children."

'Girls not brides'

According to the international coalition Girls Not Brides, girls who marry before 18 are also more vulnerable to HIV, domestic violence and malnutrition.

"I lost my job as a maid because I was pregnant. The bosses don't like it," said Cidalia Daniel, 17, who has a 10-month-old son.

According to the international coalition Girls Not Brides, girls who marry before 18 are more vulnerable to HIV, domestic violence and malnutrition.

She now lives with her parents after her husband, 21, fled abroad when she became pregnant.

"He would beat me up if I said something he didn't like. He got angry. I didn't like his behaviour," she said.

To try to help discourage parents from arranging the marriages, Mozambique in 2007 created "community committees for child protection".

"These committees are responsible for identifying cases, and contacting social workers so that they can intervene," said Ana Machaieie, from UNICEF, which trains and equips the project.

"We must make parents take responsibility, because too often they impose marriage on their own children, instead of protecting them."

Under-age marriage rates in Africa are highest in Niger, Chad and the Central African Republic.

The inaugural AU "child bride" meeting in Lusaka will focus on sharing experience of campaigns to reduce child marriage and on securing higher government funding.